Using arg parsing lib for dart2js.

Using arg parsing lib for dart2js.

Committed: https://code.google.com/p/dart/source/detail?r=7392

[Bob Nystrom, 2012-05-05 00:08:09]

I figured I'd go ahead and try out integrating my arg parser into dart2js. Let
you me what you think. A nice bonus with this change, if you invoke dart2js with
an invalid argument, you get:

Unknown option "wtf". Usage:

dart2js [options...] <entrypoint>

-h, --[no-]help                      Display usage information
    --[no-]throw-on-error            Throw an exception if a fatal error occurs
    --[no-]suppress-warnings         Display static warnings
-v, --[no-]verbose                   Display verbose output
    --[no-]allow-mock-compilation    
    --[no-]colors                    Use color when displaying output
                                     (defaults to on)

    --library-root                   Path to core lib directory
-o, --out                            Output JavaScript file to create
                                     (defaults to "out.js")

[kasperl, 2012-05-07 11:49:35]

LGTM. Thanks a lot for doing this, Bob!

It would be great if we can make the VM deal with command line arguments in a
way that is completely consistent with this (maybe then we can clean up a few
things).

https://chromiumcodereview.appspot.com/10377023/diff/1/lib/compiler/implement...
File lib/compiler/implementation/dart2js.dart (right):

https://chromiumcodereview.appspot.com/10377023/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart2js.dart:22: ArgParser parser = new
ArgParser(usage: 'dart2js [options...] <entrypoint>');
<entrypoint> -> <input>?

https://chromiumcodereview.appspot.com/10377023/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart2js.dart:27: parser.addFlag('verbose', abbr:
'v',
I'd prefer it if abbr wasn't abbreviated (feedback on lib/args).

https://chromiumcodereview.appspot.com/10377023/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart2js.dart:36: defaultsTo: 'out.js');
Indentation.

[ahe, 2012-05-07 12:49:05]

Hi Bob,

Thank you for doing this!

Changes to dart2js: LGTM

Wishes for future tweaks: I hope "[no]" can be removed from the usage message.
Also, I would like to have at least three categories of options:

1. Common options that can be documented in 80x22 in total, e.g., --help,
--enable-checked-mode, and --out.

2. Advanced options (no restriction on number of lines to document these), e.g.,
--verbose.

3. Compiler developer options that may change without notice (--throw-on-error,
--allow-mock-compilation, and --library-root are such options).

Cheers,
Peter

https://chromiumcodereview.appspot.com/10377023/diff/1/lib/compiler/implement...
File lib/compiler/implementation/dart2js.dart (right):

https://chromiumcodereview.appspot.com/10377023/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart2js.dart:21: // Set up and parse the command
line arguments.
Could you move the parser construction into a separate method?

https://chromiumcodereview.appspot.com/10377023/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart2js.dart:22: ArgParser parser = new
ArgParser(usage: 'dart2js [options...] <entrypoint>');
On 2012/05/07 11:49:35, kasperl wrote:
> <entrypoint> -> <input>?

How about <dart file> or <file>?

[Bob Nystrom, 2012-05-07 18:21:56]

On 2012/05/07 12:49:05, ahe wrote:
> Hi Bob,
> 
> Thank you for doing this!
> 
> Changes to dart2js: LGTM
> 
> Wishes for future tweaks: I hope "[no]" can be removed from the usage message.

I think it's helpful to show that so that users know it's available.

> Also, I would like to have at least three categories of options:
> 
> 1. Common options that can be documented in 80x22 in total, e.g., --help,
> --enable-checked-mode, and --out.
> 
> 2. Advanced options (no restriction on number of lines to document these),
e.g.,
> --verbose.

How would a user specify which of these they see? As much as possible, I'm
trying to keep the args library generic and simple so some use cases, even
though valid, may not be supported.

> 
> 3. Compiler developer options that may change without notice
(--throw-on-error,
> --allow-mock-compilation, and --library-root are such options).

That seems like something we could just put in the help text for those options.

Thanks!

[Bob Nystrom, 2012-05-07 18:22:05]

https://chromiumcodereview.appspot.com/10377023/diff/1/lib/compiler/implement...
File lib/compiler/implementation/dart2js.dart (right):

https://chromiumcodereview.appspot.com/10377023/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart2js.dart:21: // Set up and parse the command
line arguments.
On 2012/05/07 12:49:06, ahe wrote:
> Could you move the parser construction into a separate method?

Done.

https://chromiumcodereview.appspot.com/10377023/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart2js.dart:22: ArgParser parser = new
ArgParser(usage: 'dart2js [options...] <entrypoint>');
On 2012/05/07 12:49:06, ahe wrote:
> On 2012/05/07 11:49:35, kasperl wrote:
> > <entrypoint> -> <input>?
> 
> How about <dart file> or <file>?

<input entrypoint dart file>? ;)

Changed to <dart file>

https://chromiumcodereview.appspot.com/10377023/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart2js.dart:27: parser.addFlag('verbose', abbr:
'v',
On 2012/05/07 11:49:35, kasperl wrote:
> I'd prefer it if abbr wasn't abbreviated (feedback on lib/args).

I'm not crazy about it either. I think I'll change it to "short" in a later
patch.

https://chromiumcodereview.appspot.com/10377023/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart2js.dart:36: defaultsTo: 'out.js');
On 2012/05/07 11:49:35, kasperl wrote:
> Indentation.

Done.